The Ford Barn

Paul Bennett · 07-09-2017, 07:25 PM

All this "technically correct' is NOT technically correct. Ammeters do NOT measure flow but measure voltage across a fixed resistance calibrated (or not) in Amps using a d'Arsenval movement.

Ford applications of 'Gas Level' 'Oil Pressure' and 'Temperature' do NOT use d'Arsenval movement gauges but THERMOSTATIC gauge which, as JSeary has tried to point out, is different.

Resistance senders were considered hazardous early on because the armature must transition from one coil to the next. So Ted Smulski invented and patented the thermostatic gauge system, which is odd considering the sender must open and close a set of terminals in the flammable fluid.

Ted's patent used the term 'thermostatic gauge' - it was assigned to Anderson Corp who contracted King-Seeley to manufacture gauges/senders. The patent claims was compact, convenient, duragle and not sensitive to voltage.

Senders - resistance vs thermostatic. Actually, were a d'Arsonval meter be used with a thermostatic sender, the gauge would pulse hi-lo-hi-lo but a thermostatic meter evens out the peaks and presents a true ratio of on-off periods.

Ironically, a year after the Smulski patent, Joe Zublaty was granted a patent on a resistance gauge because the flamability nature of gasoline was found not a danger with a resistance sender. A galvanometer or ohm meter was used for the readout.

King-Seeley filed for a resistance gauge patent in 1954 obviously with knowlege of Ford's conversion to 12v. I've heard Ford switched to resitance fuel gauge in 1955 for one year switching back until 1980 but can't confirm it.

07-09-2017, 07:25 PM	#19
Paul Bennett Senior Member Join Date: Sep 2016 Posts: 628	Re: How Ford Gauge Unit Work All this "technically correct' is NOT technically correct. Ammeters do NOT measure flow but measure voltage across a fixed resistance calibrated (or not) in Amps using a d'Arsenval movement. Ford applications of 'Gas Level' 'Oil Pressure' and 'Temperature' do NOT use d'Arsenval movement gauges but THERMOSTATIC gauge which, as JSeary has tried to point out, is different. Resistance senders were considered hazardous early on because the armature must transition from one coil to the next. So Ted Smulski invented and patented the thermostatic gauge system, which is odd considering the sender must open and close a set of terminals in the flammable fluid. Ted's patent used the term 'thermostatic gauge' - it was assigned to Anderson Corp who contracted King-Seeley to manufacture gauges/senders. The patent claims was compact, convenient, duragle and not sensitive to voltage. Senders - resistance vs thermostatic. Actually, were a d'Arsonval meter be used with a thermostatic sender, the gauge would pulse hi-lo-hi-lo but a thermostatic meter evens out the peaks and presents a true ratio of on-off periods. Ironically, a year after the Smulski patent, Joe Zublaty was granted a patent on a resistance gauge because the flamability nature of gasoline was found not a danger with a resistance sender. A galvanometer or ohm meter was used for the readout. King-Seeley filed for a resistance gauge patent in 1954 obviously with knowlege of Ford's conversion to 12v. I've heard Ford switched to resitance fuel gauge in 1955 for one year switching back until 1980 but can't confirm it.